Laminated Color Filter Sub-layers for Organic EL Devices
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Solution Overview
Problem
The existing methods for manufacturing organic EL devices face challenges in achieving high color reproducibility due to the formation of tapered shapes in color filter layers, which reduces the region with predetermined thickness, affecting pixel pitch and overall display quality.
Innovation Solution
The organic EL device incorporates a configuration with laminated sub-filter layers of the same material, overlapping each other to form a color filter layer, which reduces the width of tapered portions and ensures a broader region with predetermined thickness, along with a flattened layer to facilitate even formation and a light-shielding layer to prevent color mixing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the film thickness of the color filter layer is thickened to ensure predetermined thickness for high color reproducibility, then color reproducibility is improved, but the formation region of tapered shape increases, reducing the effective pixel area
Solution Approach 1:
The color filter layer is divided into multiple sub-filter layers (first sub-filter layer, second sub-filter layer, etc.) that are formed by separate photolithographic processes. Each sub-filter layer has a smaller tapered shape formation region, and when laminated together, they create a color filter layer with sufficient overall thickness while minimizing the total tapered portion area that would otherwise require a single thick layer
Solution Approach 2:
Instead of increasing thickness in the vertical dimension (which exacerbates tapered shape formation in a single layer), the patent distributes the thickness requirement across multiple layers stacked in the vertical dimension. This dimensional approach allows the total optical path length to be achieved while each individual layer maintains a smaller lateral footprint, reducing the tapered portion area
Data Source
AI summary
An organic EL device includes a substrate; a color filter layer that is formed above the substrate; a first electrode that is formed between the substrate and the color filter layer; a second electrode that is formed to face the first electrode; and an organic light-emitting layer that is formed between the first and second electrodes. The color filter layer includes first and second sub-filter layers that are formed in a region overlapping the first electrode, when viewed from a direction perpendicular to the substrate, and transmit a first color. The first and second sub-filter layers are formed of the same material and the first and second sub-filter layers are laminated.